Installing A Heat-Recovery Ventilator

Poorly ventilated homes can have high core, or a rotary wheel core (Figure 2).
Parallel-plate cores, whether counterflow
or crossflow, are made of aluminum,
plastic, or, in the case of an
energy-recovery ventilator, a moisturepermeable
membrane (see “Energy-
Recovery Ventilators,” next page).
Some manufacturers tout the theoretical
superiority of counterflow cores
over crossflow cores, or aluminum
components over polypropylene. In
practice, however, HRV efficiency
depends upon many design factors, not
just core geometry or material type. The
best resource for comparing HRV efficiencies
is the Product Directory published
by the Home Ventilating Institute
(available online at www.hvi.org, or by
calling 847/394-0150). When choosing
an HRV, small differences of efficiency
may be less important than the level of
service provided by a